Interpretive Summary: Dextranase enzymes (chemical that speeds up a reaction) are sometimes applied to break down dextran (a long chain sugar molecule) in sugar manufacture. Unfortunately, less than optimum application of dextranaseas previously existed because of confusion about where to add the dextranase in the factory and which commercial dextranase to use. Optimization by applying high strength dextranase as a working solution to sugar beet juice is described, as well as factory trials conducted at Wissington factory of British Sugar in the UK. The trials demonstrated a significant benefit on juice clarification, which resulted in increased factory throughput rates and improved operational stability, which were cost-effective.

Technical Abstract:
Dextranases are sometimes applied to hydrolyze dextran polysaccharide in sugar manufacture when bacterial deterioration of sugar beet has occurred. Unfortunately, dextranases only have a small market and low volume sales compared to many other industrial enzymes. Consequently, research and development efforts to engineer properties of dextranases to specific conditions of sugar beet processing have not occurred and are not expected soon. Less than optimum application previously existed because of confusion about where to add the dextranase in the factory and which commercial dextranase to use. The wide variation in activity of commercially available dextranases in the U.S., Europe and other parts of the world, and a standardized titration method to measure activities at the factory are discussed. The titration method to measure the activity of dextranases at the factory is currently an ICUMSA (International Commission for Uniform Methods in Sugar Analysis) draft method. Optimization by applying “concentrated” dextranase as a working solution to juice is described. The results and conclusions from a trial of dextranase addition to draft raw juice at Wissington factory in the UK are discussed with emphasis on the impact on factory throughput and other key operational parameters. The trial demonstrated a significant benefit on second carbonatation filtration which resulted in increased throughput, reduction in process chemicals usage, improved operational stability, a reduction in limesalts, and a reduction in the amount of water discharged to the site effluent treatment plant. A concentrated dextranase gave better cost in use, because an addition rate below that recommended by the suppliers was achieved making the product significantly cheaper.